In an image forming apparatus, such as a copying machine or the like, exposure means is reciprocatively moved along a document table by the operation of a scan motor, and at the time of the going forth motion, the document table is scanned and is exposed to read an image on a document so that the read image is formed on a sheet of copy paper that is an image formed medium. A pulse motor is employed as the scan motor.
The exposure means has an exposure lamp and a carriage on which the exposure lamp is mounted as the components thereof. The carriage is reciprocatably provided along the document table and is coupled with a shaft of the scan motor via a power transmission mechanism, such as a belt, a wire, and the like so as to reciprocate, while receiving the power of the scan motor.
When the carriage goes forth, the scan motor first operates acceleratively to a target speed, then operates by a constant speed after reaching the target speed, and finally operates deceleratively. During the period in which the scan motor operates by a constant speed, the image on the document is read. When the carriage goes back, also, the scan motor first operates acceleratively, then operates by a constant speed, and finally operates deceleratively.
Drive control data for the scan motor of the time of going forth motion and drive control data for the scan motor of the time of going back motion are stored in storage means, for example, a memory.
If the amount of the drive control data is large, the capacity of the memory is increased, thereby causing an increase in the cost.
The present invention is developed, considering the above described circumstances, and it is an object of the present invention to provide an image forming apparatus and method of controlling the apparatus wherein the drive control data for the motor for the exposure means can be reduced considerably, whereby the capacity of the storage means can be reduced or an empty capacity of the storage means can be increased to enable an effective utilization of the empty capacity.
An image forming apparatus of the present invention reciprocatively operates exposure means along a document table by an operation of a motor, scans and exposes the document table when the exposure means goes forth to read the image of the document, and forms the read image on an image formed medium, the apparatus comprising first control means for first acceleratively operating, then operating by a constant speed, and finally deceleratively operating the motor when the exposure means goes forth and second control means for operating the motor by a constant speed from beginning to end when the exposure means goes back.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.